The magnesium desulfuration process is a flue gas treatment process commonly used in the medium-sized and small-sized industrial boilers in China, and the rationale of the process is that using an aqueous solution of magnesium oxide as an absorbing agent, thereby sulfur dioxide in a flue gas is absorbed to produce magnesium sulfite, which is oxidized to produce a magnesium sulfate solution. This process is featured by high desulfuration efficiency, low investment, low land occupation, stable operation and so on, and hence develops very fast in China recently.
In practical operation, since the oxidation reaction rate of magnesium sulfite (the by-product of the magnesium desulfuration process) is relatively low, and insufficient oxidation of magnesium sulfite tends to bring about issues of system scaling, blocking, low product quality, secondary pollution of effluents and so on, causing a relatively high investment and high energy consumption of the recovery process of desulfuration by-product. At the present time, the above problem is solved by adding transitional metal catalyst, and this can significantly improve the oxidation capacity of the system without changing the blow rate of the oxidizing gas and hence has good application prospect. However, since the catalyst is added in a solution form into the desulfuration slurry, operation cost of the application process is high; meanwhile, the catalyst being difficult to be recovered will inevitably cause secondary pollution of heavy metal(s) in the desulfuration by-product and effluents. Therefore, the application and popularization of the catalyst is greatly limited.